We have a Windows 2003 RAS server that has been working for a while when it
suddenly stops working. When we enable the RAS server using "Routing and
Remote Access", RAS clients are able to connect, but clients on LAN cannot
connect or ping the RAS server and vice versa. It displays an unrecognized
PPP adapter when we do "ipconfig / all" command. The following is how it
looks like:

We suspect that the PPP adapter has something to do with the problem above.
We have tried several different things (rebooting the server, netsh int ip
reset, route delete 192.168.234.235, disabling the built in network adapter
in BIOS) to try to remove the PPP adapter, but none of them works. The
following is our RAS server IP info:

The PPP adapter is usually a virtual adapter for a VPN connection. Where did
the 192.168.234 address come from? Since it didn't get it via DHCP, it must
have been assigned. What connections are showing in Network Properties? Do
you have a VPN connection to somewhere else on the same box? That's not
something I'd recommend, altough you can do it (I've done it). It takes some
manual setup. If you do, you'll probably need to manually set up your
routing table.